Short Chain Fatty Acids Concentration in StoolsNCT07550023
Effects Of Dietary Fats on Gut Microbiota Composition and Metabolic Activity in Healthy Adults
A study testing Butter, Coconut oil and Extra Virgin Olive Oil in people with Short Chain Fatty Acids Concentration in Stools and Gut Microbiota Diversity and Composition, run by University of Glasgow at 1 site in United Kingdom.
Trial summary
This study will investigate how adding a specific type of dietary fat to daily meals for two weeks affects the gut bacteria and their activity. Participants will be randomly assigned to consume one of four types of fat: butter, coconut oil, olive oil, or sunflower oil (60 mL each day for 2 weeks). Read more about this study
- Who is it for?
- Ages 20 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Short Chain Fatty Acids Concentration in Stools, Gut Microbiota Diversity and Composition, Blood Lipid Profiles
- What is being tested?
- Butter, Coconut oil and Extra Virgin Olive Oil
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 64 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 23 Mar 2026to 31 Mar 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Adults aged 20-50 years
- Body mass index (BMI) between 20 and 30 kg/m²
- Generally healthy
- Stable body weight (±2 kg) over the past 2 months
- Living in the Glasgow area
- Non-smoker
Who cannot join
- Use of antibiotics within the past 3 months
- Current use of medications affecting gut microbiota or cardiometabolic health
- Regular use of dietary supplements that may influence study outcomes (e.g. probiotics, prebiotics, vitamins, minerals, fish oil), unless willing to discontinue prior to study start
- Presence of chronic gastrointestinal, metabolic, cardiovascular, hepatobiliary, or pancreatic disease
- History of major gastrointestinal surgery
- Diagnosed diabetes or use of lipid-lowering therapy
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- Known fat malabsorption disorders
- Pregnant or lactating women
- Post-menopausal women
- Following a restrictive or specific diet (e.g. vegan, ketogenic diet)
- Food allergies or intolerances relevant to study interventions (e.g. dairy, coconut)
- Recent significant weight change (±2 kg in the past month)
- High reliance on ready meals or takeaway foods (>7 main meals per week)
- Participation in another research study that may interfere with this study
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Athanasios Koutsos contact
United Kingdom1 site, 1 recruiting
- Recruiting
New Lister Building, Glasgow Royal Infirmary, 10-16 Alexandra Parade, G31 2ER
Glasgow, G31 2ER
Athanasios Koutsos, 138629-01, Athanasios.Koutsos@glasgow.ac.uk
Athanasios Koutsos
About this study
This study will investigate how adding a specific type of dietary fat to daily meals for two weeks affects the gut bacteria and their activity. Participants will be randomly assigned to consume one of four types of fat: butter, coconut oil, olive oil, or sunflower oil (60 mL each day for 2 weeks). Stool and blood samples (after an overnight fast) will be collected at 3 time points during the study (Days 1, 7, and 22). These samples will be used to measure metabolites produced by gut bacteria, the types of bacteria present in the gut, blood lipids, and inflammatory markers. The study, based on previous in vitro findings, aims to understand whether different types of fats (based on their structure and level of saturation) have different effects on gut bacteria and their activity in healthy subjects.
Read the detailed description
This is a pilot, parallel, randomised controlled dietary intervention trial investigating the effects of dietary fat composition on gut microbiota and metabolic activity in healthy adults. Participants will be randomised to one of four intervention groups (butter, coconut oil, extra virgin olive oil, or sunflower oil), representing commonly consumed dietary fats that differ in fatty acid structure.
This study builds on prior in vitro findings demonstrating that fatty acid chain length and degree of saturation influence microbial fermentation pathways and short-chain fatty acid (SCFA) production.
The primary objective is to determine whether structurally distinct dietary fats differentially influence gut microbial activity and composition in vivo. Secondary objectives include assessing the effects on cardiometabolic and inflammatory markers. It is hypothesised that dietary fats differing in chain length and degree of saturation will differentially modulate gut microbiota metabolism, with potential systemic effects on circulating cardiometabolic and inflammatory markers.
A total of 64 healthy adults aged 20-50 years will be recruited from the Glasgow area. All study visits will take place at the New Lister Building, University of Glasgow. Participants will attend three study visits over a three-week period.
The study includes a one-week run-in period (normal habitual diet) followed by a two-week dietary intervention. During the intervention, participants will replace the majority of their habitual dietary fat intake with their allocated fat while maintaining their usual diet and lifestyle.
Biological samples (blood and stool) will be collected at each study visit (Day 1, 7 and 22) to assess study outcomes. Anthropometric measurements will also be recorded. Dietary intake, gastrointestinal symptoms, and compliance will be monitored using food diaries, symptom questionnaires, and adherence logs.
The sample size is based on anticipated changes in faecal SCFA concentrations. Based on prior data, 14 participants per group provides 80% power (P=0.05) to detect a mean change of 30 μmol/g (SD: 28 μmol/g). Allowing for a 10% drop-out rate, 16 participants per group (64 total) will be recruited. As this is a pilot study, this calculation is intended to inform a reasonable sample size rather than to ensure definitive hypothesis testing.
- Conditions
- Short Chain Fatty Acids Concentration in Stools, Gut Microbiota Diversity and Composition, Blood Lipid Profiles, Inflammation Biomarkers
- Being tested
- Butter, Coconut oil, Extra Virgin Olive Oil, Sunflower Oil
- Keywords
- Gut microbiome, Gut microbiota, Dietary fat, Short-chain fatty acids, SCFA, Saturated fat, Monounsaturated fat, Polyunsaturated fat, Butter, Olive oil, Coconut oil, Sunflower oil, MUFA, PUFA
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ButterOther
Participants will consume approximately 65 g/day of butter as their primary dietary fat for 14 days, replacing most habitual dietary fat intake.
Coconut oilOther
Participants will consume approximately 55 g/day of coconut oil as their primary dietary fat for 14 days, replacing most habitual dietary fat intake.
Extra Virgin Olive OilOther
Participants will consume 60 mL/day of olive oil as their primary dietary fat for 14 days, replacing most habitual dietary fat intake.
Sunflower OilOther
Participants will consume 60 mL/day of sunflower oil as their primary dietary fat for 14 days, replacing most habitual dietary fat intake.
| Study group | Role | What they receive |
|---|---|---|
| Butter | Experimental | Following a one week run-in period (habitual diet), participants will be assigned to consume butter as their primary dietary fat. Receives: Other: Butter |
| Coconut Oil | Experimental | Following a one week run-in period (habitual diet), participants will be assigned to consume coconut oil as their primary dietary fat. Receives: Other: Coconut oil |
| Extra Virgin Olive Oil | Experimental | Following a one week run-in period (habitual diet), participants will be assigned to consume olive oil as their primary dietary fat. Receives: Other: Extra Virgin Olive Oil |
| Sunflower Oil | Experimental | Following a one week run-in period (habitual diet), participants will be assigned to consume sunflower oil as their primary dietary fat. Receives: Other: Sunflower Oil |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in faecal short-chain fatty acid (SCFA) concentrations
Faecal concentrations of short-chain fatty acids (acetate, propionate, and butyrate) will be measured using gas chromatography to assess changes in gut microbial metabolic activity in response to dietary fat intervention.
Measured: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in gut microbiota composition
Gut microbiota composition will be assessed using 16S rRNA gene amplicon sequencing to evaluate changes in bacterial diversity and relative abundance following the dietary fat intervention.
Measured: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Secondary outcomes (5)
Change in blood lipid profile
Fasting blood concentrations of total cholesterol, LDL-cholesterol, HDL-cholesterol, and triglycerides will be measured using standard enzymatic assays to assess cardiometabolic responses to the dietary fat intervention.
Measured: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in inflammatory markers
Circulating inflammatory markers (e.g., C-reactive protein (CRP), interleukin-6 (IL-6)) will be measured using ELISA or multiplex assays to assess systemic inflammatory responses to the dietary fat intervention.
Measured: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in faecal pH
Faecal pH will be measured to assess changes in the gut environment associated with microbial fermentation.
Measured: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in fasting glucose concentrations
Fasting blood glucose concentrations will be measured to assess changes in glucose metabolism in response to dietary fat intake.
Measured: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in faecal fat content
Faecal fat content will be measured to assess fat excretion and potential differences in fat digestion and absorption across intervention groups.
Measured: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Apr 2026
- Study start23 Mar 2026
- Primary completion31 Mar 2027 (estimated)
- Study completion31 Mar 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Short Chain Fatty Acids Concentration in StoolsStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 64 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Glasgow
- Sponsor type
- University, hospital or other
- Collaborators
- Dr Dalia Malkova, Professor Konstantinos Gerasimidis
- Responsible party
- Principal investigator, Athanasios Koutsos, University of Glasgow
- Investigators
- Athanasios Koutsos, Principal investigator, University of GlasgowDalia Malkova, PhD, Principal investigator, University of GlasgowKonstantinos Gerasimidis, PhD, Principal investigator, University of Glasgow
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07550023
- Sponsor's protocol ID
- 200250221
- Status last verified
- Apr 2026
- First submitted
- 17 Apr 2026
- Last updated
- 24 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 24 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects Of Dietary Fats on Gut Microbiota Composition and Metabolic Activity in Healthy Adults
- ClinicalTrials.gov ID
- NCT07550023
- Acronym / sponsor ID
- 200250221
- Conditions
- Short Chain Fatty Acids Concentration in Stools, Gut Microbiota Diversity and Composition, Blood Lipid Profiles, Inflammation Biomarkers
- Keywords
- Gut microbiome, Gut microbiota, Dietary fat, Short-chain fatty acids, SCFA, Saturated fat, Monounsaturated fat, Polyunsaturated fat
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 64 participants (estimated)
- Lead sponsor
- University of GlasgowUniversity, hospital or other
- Collaborators
- Dr Dalia Malkova, Professor Konstantinos Gerasimidis
- Study start
- 23 Mar 2026 (actual)
- Primary completion
- 31 Mar 2027 (estimated)
- Study completion
- 31 Mar 2028 (estimated)
- First posted
- 24 Apr 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will investigate how adding a specific type of dietary fat to daily meals for two weeks affects the gut bacteria and their activity. Participants will be randomly assigned to consume one of four types of fat: butter, coconut oil, olive oil, or sunflower oil (60 mL each day for 2 weeks). Stool and blood samples (after an overnight fast) will be collected at 3 time points during the study (Days 1, 7, and 22). These samples will be used to measure metabolites produced by gut bacteria, the types of bacteria present in the gut, blood lipids, and inflammatory markers. The study, based on previous in vitro findings, aims to understand whether different types of fats (based on their structure and level of saturation) have different effects on gut bacteria and their activity in healthy subjects.
Detailed description
This is a pilot, parallel, randomised controlled dietary intervention trial investigating the effects of dietary fat composition on gut microbiota and metabolic activity in healthy adults. Participants will be randomised to one of four intervention groups (butter, coconut oil, extra virgin olive oil, or sunflower oil), representing commonly consumed dietary fats that differ in fatty acid structure.
This study builds on prior in vitro findings demonstrating that fatty acid chain length and degree of saturation influence microbial fermentation pathways and short-chain fatty acid (SCFA) production.
The primary objective is to determine whether structurally distinct dietary fats differentially influence gut microbial activity and composition in vivo. Secondary objectives include assessing the effects on cardiometabolic and inflammatory markers. It is hypothesised that dietary fats differing in chain length and degree of saturation will differentially modulate gut microbiota metabolism, with potential systemic effects on circulating cardiometabolic and inflammatory markers.
A total of 64 healthy adults aged 20-50 years will be recruited from the Glasgow area. All study visits will take place at the New Lister Building, University of Glasgow. Participants will attend three study visits over a three-week period.
The study includes a one-week run-in period (normal habitual diet) followed by a two-week dietary intervention. During the intervention, participants will replace the majority of their habitual dietary fat intake with their allocated fat while maintaining their usual diet and lifestyle.
Biological samples (blood and stool) will be collected at each study visit (Day 1, 7 and 22) to assess study outcomes. Anthropometric measurements will also be recorded. Dietary intake, gastrointestinal symptoms, and compliance will be monitored using food diaries, symptom questionnaires, and adherence logs.
The sample size is based on anticipated changes in faecal SCFA concentrations. Based on prior data, 14 participants per group provides 80% power (P=0.05) to detect a mean change of 30 μmol/g (SD: 28 μmol/g). Allowing for a 10% drop-out rate, 16 participants per group (64 total) will be recruited. As this is a pilot study, this calculation is intended to inform a reasonable sample size rather than to ensure definitive hypothesis testing.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Butter | Experimental | Other: ButterFollowing a one week run-in period (habitual diet), participants will be assigned to consume butter as their primary dietary fat. |
| Coconut Oil | Experimental | Other: Coconut oilFollowing a one week run-in period (habitual diet), participants will be assigned to consume coconut oil as their primary dietary fat. |
| Extra Virgin Olive Oil | Experimental | Other: Extra Virgin Olive OilFollowing a one week run-in period (habitual diet), participants will be assigned to consume olive oil as their primary dietary fat. |
| Sunflower Oil | Experimental | Other: Sunflower OilFollowing a one week run-in period (habitual diet), participants will be assigned to consume sunflower oil as their primary dietary fat. |
Who may qualify
- Ages
- 20 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Adults aged 20-50 years
- Body mass index (BMI) between 20 and 30 kg/m²
- Generally healthy
- Stable body weight (±2 kg) over the past 2 months
- Living in the Glasgow area
Key exclusion criteria (14 listed)
- Use of antibiotics within the past 3 months
- Current use of medications affecting gut microbiota or cardiometabolic health
- Regular use of dietary supplements that may influence study outcomes (e.g. probiotics, prebiotics, vitamins, minerals, fish oil), unless willing to discontinue prior to study start
- Presence of chronic gastrointestinal, metabolic, cardiovascular, hepatobiliary, or pancreatic disease
- History of major gastrointestinal surgery
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ButterParticipants will consume approximately 65 g/day of butter as their primary dietary fat for 14 days, replacing most habitual dietary fat intake. | Other | Butter |
| Coconut oilParticipants will consume approximately 55 g/day of coconut oil as their primary dietary fat for 14 days, replacing most habitual dietary fat intake. | Other | Coconut Oil |
| Extra Virgin Olive OilParticipants will consume 60 mL/day of olive oil as their primary dietary fat for 14 days, replacing most habitual dietary fat intake. | Other | Extra Virgin Olive Oil |
| Sunflower OilParticipants will consume 60 mL/day of sunflower oil as their primary dietary fat for 14 days, replacing most habitual dietary fat intake. | Other | Sunflower Oil |
Primary outcome
Change in faecal short-chain fatty acid (SCFA) concentrations
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Faecal concentrations of short-chain fatty acids (acetate, propionate, and butyrate) will be measured using gas chromatography to assess changes in gut microbial metabolic activity in response to dietary fat intervention.
Change in gut microbiota composition
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Gut microbiota composition will be assessed using 16S rRNA gene amplicon sequencing to evaluate changes in bacterial diversity and relative abundance following the dietary fat intervention.
5 secondary outcomes
Change in blood lipid profile
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in inflammatory markers
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in faecal pH
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in fasting glucose concentrations
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Change in faecal fat content
Time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Apr 2026.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Athanasios Koutsos contact
Athanasios Koutsos principal investigator
University of Glasgow
Dalia Malkova, PhD principal investigator
University of Glasgow
Konstantinos Gerasimidis, PhD principal investigator
University of Glasgow
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Butter, Coconut oil and Extra Virgin Olive Oil in people with Short Chain Fatty Acids Concentration in Stools and Gut Microbiota Diversity and Composition, run by University of Glasgow at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 24 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Linah Alhomidan (+447473477395, linahalhomidan@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in faecal short-chain fatty acid (SCFA) concentrations (time frame: Day 1 (pre run-in), Day 7 (baseline, post run-in), and Day 22 (post-intervention)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Apr 2026.